1. Field of the Invention
The present invention relates to a touch device, and particularly to an optical touch device and a locating method thereof, and a linear light source module.
2. Description of the Related Art
Nowadays, a touch function has been one of necessary functions of many electronic devices. A touch device is an important component to achieve the touch function. Generally, a familiar type of the touch device is, for example, a resistive touch device, a capacitive touch device or an optical touch device. The electronic devices can be equipped with various touch devices in accordance with the various demands.
FIG. 1 is a schematic view of a conventional optical touch device. Referring to FIG. 1, the conventional optical touch device 100 includes a light guide module 110, a light emitting component 120 and an image detecting module 130. The light guide module 110 includes two light guide bars 112a and 112b and a mirror bar 114. The light guide bars 112a and 112b and the mirror bar 114 are arranged along three sides of a rectangle. The light guide bar 112a faces to the mirror bar 114 and the light guide bar 112b is connected between the light guide bar 112a and mirror bar 114. The area in the rectangle defines a detecting area 116. In addition, the light emitting component 120 is disposed between two neighboring ends of the light guide bar 112a and the light guide bar 112b and is configured for emitting light into the light guide bar 112a and the light guide bar 112b. The light guide bar 112a and the light guide bar 112b are configured for converting the light from the light emitting component 120 into a linear light to irradiate the detecting area 116. The image detecting module 130 is disposed besides the light guide bar 112a. A field of view (FOV) of the image detecting module 130 covers the detecting area 116.
The image detecting module 130 is configured for detecting a touch point (i.e., a light blocking object) in the detecting area 116 and calculating a position of the touch point. In detail, the touch point A in the detecting area 116 has a mirror point A1 formed by the mirror bar 114. Meanwhile, the image detecting module 130 can detect dark points A2 and A3. Thus, distances d1 and d2 can be calculated. Then, according to the distances d1 and d2 and other known parameters, the position (i.e., coordinates) of the touch point A can be calculated. The other known parameters mentioned above include a length of the detecting area 116 along the X axis, a width of the detecting area 116 along the Y axis, a shortest distance between the touch point A and the mirror bar 114 that is equal to a shortest distance between the mirror point A and the mirror bar 114, and so on. A detailed calculating method of the position of the touch point A is familiar to one skilled in the art and is not be described here.
However, the conventional optical touch device 100 has a blind zone 150 as shown in FIG. 1. The blind zone 150 refers to an area in the detecting area 116 where the coordinates of the touch point can not be calculated accurately. For example, the touch point B in the detecting area 116 is just located in the blind zone 150 so that the dark points B2 and B3 detected by the image detecting module 130 are overlapped partially. Thus, the coordinates of the touch point B can not be calculated accurately.
FIG. 2 is a schematic view of another conventional optical touch device. Referring to FIG. 2, the conventional optical touch device 100a is similar to the conventional optical touch device 100 except that the light guide module 110a includes two light guide bars 112a and 112b and two mirror bars 114a and 114b. The light guide bar 112a is adjacent to the light guide bar 112b, and the mirror bar 114a is adjacent to the mirror bar 114b. The light guide bars 112a and 112b and the mirror bars 114a and 114b are arranged along four sides of a rectangle. The area in the rectangle defines a detecting area 116.
Comparative to the conventional optical touch device 100, although the area of the blind zone 150a of the conventional optical touch device 100a has been decreased, the problem of the blind zone as mentioned above still exists. In addition, because the light guide module 110a of the conventional optical touch device 100a includes two mirror bars 114a and 114b, one touch point in the detecting area 116 will generate three mirror points correspondingly. Thus, the image detecting module 130 will detect more dark points than the conventional optical touch device 100, thereby increasing the complexity of calculating the coordinates of the one touch point.
Furthermore, when two touch points are simultaneously in the detecting area 116, six mirror points corresponding to the two touch points will generate. Thus, the complexity of calculating the coordinates of the two touch points will be increased greatly. Therefore, the conventional optical touch device 100a is unsuitable to be used as a dual-touch device or a multi-touch device.